Adsorption of Salivary Protein to Resin Composite Containing S-PRG Filler

Abstract

The purpose of this study was to clarify the anti-plaque mechanism of a composite resin containing S-PRG filler and to examine both in (in vitro and in vivo) the protein adsorption modality on the surface of the composite resin. The tested materials were; composite resin containing 40wt% S-PRG filler, the base resin and bovine enamel. In addition, the four components of a resin composite product that contain S-PRG filler (Beautifil) were used; S-PRG filler, MF (multi functional) glass filler, ultrafine particle alumina filler and powdered base resin. Blocks of S-PRG filler resin and base resin were prepared and attached to the buccal surface of the upper first molar in the mouth for 2, 8 and 24 hours, respectively. After that, the blocks were observed under a scanning electron microscope (SEM), analyzed with an energy dispersive X-ray micro analyzer (EDX) and an electron probe micro analyzer (EPMA). Subsequently, examination of the total protein adsorption rate was performed in vitro by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method. Each supply material was soaked in human saliva for the SDS-PAGE analysis. The protein band was detected by silver staining after electrophoresis, and the molecular weight of the protein was calculated from a relative mobility. Furthermore, protein adsorption was analyzed in vivo by the immunity SEM method, and five kinds of proteins were selected (Mucin1, Lactoferrin, IgA, Cystatin-C, Lysozyme) as the first antibody. As a result, the SEM observation showed that both surfaces (S-PRG filler resin and base resin) were similar after the blocks were removed from the mouth; however, the EDX analysis showed different components (F, Al, Si, Sr) in their structures. Moreover, the formation of mature dental plaque was witnessed in the base resin, even though the adhesion of plaque on the surface of S-PRG filler resin tended to be localized. Additionally, greater concentration of nitrogen was detected by EPMA in S-PRG filler resin and base resin after the blocks were removed from the mouth. The electrophoresis analysis exhibited that S-PRG filler has the property to adsorb 14kDa of saliva proteins. The main proteins detected on the surface of S-PRG filler resin by the immunity SEM method were Cystatin-C and Lysozyme. For S-PRG filler resin and S-PRG filler, the antibodies molecular weights were similar to the molecular weights obtained in the electrophoresis analysis that was previously carried out in vitro. The structure of the pellicle formed on the surface of the resin composites and the adsorption of the saliva proteins were examined in vitro and confirmed in vivo. Numerous anti-bacterial proteins were detected on the surface of S-PRG filler resin; therefore, the proteins composition could control in some way the formation of dental plaque.